Internal combustion engine



April 6, 1937. A. ROTH INTERNAL COMBUSTION ENGINE 2 Shets-Sheet 1 FiledOct. 9, 1933 April-6, 1937. A. ROTH INTERNAL COMBUSTION ENGINE FiledOct; 9, 19:55 7 2 Shets-Sheet 2 M mm Patented Apr. 6, 1937 v I PATENT.OFFICE INTERNAL COMBUSTION ENGINE Adolf Roth, Essen, Germany, assignorto Fried. Krupp Aktiengesellschaft, Essen-on-the-Rnhr,

Application 2, Claims.

The invention relates to internal combustion engines and has moreparticularly reference to A further object of the invention is to renderas simple as possible the conversion from one into the other type ofengine.

With these ends in view, the invention primarily consists in the factthat a fuel feeding device, such as an antechamber body, is mounted inthe wall of the working cylinder of the Diesel engine in the range ofthe top dead center transversely of the axis of the cylinder. 25 Theinvention further consists in the fact that the fuel feeding device,that is the antechamber body, of the Diesel engine is adapted to bereplaced by a spark plug or a corresponding member as used in lowcompression engines operating 30 on a carbureted mixture.

The invention is of great importance when applied to air-cooled internalcombustion engines. In engines of this type, in the case of anantechamber Diesel engine, the current of cool- 35 ing air for theworking cylinder also cools at least a part of the antechamber body and,in the case of a Diesel engine with direct fuel injection, the injectionnozzle is cooled in a corresponding manner.

In order that the invention may be clearly understood and more readilyput into practice, it is explained hereinafter with reference to theaccompanying drawings which show a horizontal Diesel engine providedwith an antechamber, 45 this engine-being obtained by converting a lowcompression engine in accordance with the principle' of the invention.In the drawings:

Figure 1 is a central longitudinal section of the engine,

Figure 2 is a section 1, and

Fig. 3 is a plan view of the head of the piston shown in Figs. 1 and'2.

v The reference numeral I denotes the hori- 55 zontal working cylinderof a low compression 50 n line II-II of Figure October 9, 1933, SerialNo. 692,885 Germany November 1, 1932 engine. The cylinder l is providedat its outer end with cooling ribs 2 extending parallel to thelongitudinal axis of the cylinder. The cooling ribs 2'are surrounded bya casing 3 through which air isforced in the direction of arrow m,Figure 1, by means of a fan (not shown) mounted on the crank shaft ofthe engine. on the outer end of the cylinder I there is mounted acylinder head 4 in which an admission valve Ii and an outlet valve 6 areprovided. As far as disclosed in the foregoing, this engine isconventional.

The working piston l of the engine differs from the normal piston of alow compression engine by the smaller clearance space 8 existing betweenit and the cylinder head 4 when. the piston is at the top dead centerposition. I To this end the piston 1 has a trough-shaped indentation 9on its top face, see also Figure 2, which extends in the direction of .adiameter of piston I. The indentation 9 has the greatest depth at itsuppermost end Ill and gradually decreases in depth and width toward theopposite point II of the piston down to zero. In line with thelongitudinal axis of the indentation! is arranged a two-part antechamberbody .12 which is removably mounted in the cylinder wall I instead ofthe sparking plug or other suitable ignition means usual with lowcompression engines. The antechamber contained in the body I2 is ofoblong shape and is confined on its end turned toward the cylinder I bya partition IS in which a number of passages, such as l4, for examplethree, are provided. On its opposite end a fuel nozzle IGopens into theantechamber I3, which nozzle forms the end of a fuel duct II fed bymeans of a suitable fuel pump (not shown). The fuel nozzle I6 is mountedin a body I9 provided with transverse ribs l8 and screwed into anotherbody 2| which is formed with the wall I5 and likewise is provided withtransverse ribs 20. The two parts l9 and 2| form together theantechamber body I2. The part 2| further is formed with a socket 22directed toward the wall I5 and having mounted in it an ignition device,for example a spark plug 23, which serves to secure the ignition of thefuel in the antechamber I3 upon starting, that is, when the engine isstill cold. The passages I4 in the partition I5 are arranged in a planetransverse to the axis of the working piston I, that is, in a verticalplane normal to the direction of motion of the piston 'l. The locationof the passages I4 in juxtaposition and, further, at half the depth ofthe indentation 9 of the piston I has for its bodiment illustrated, moreor less passages may object to secure uniform mixing with the aircontained in the space 8 of the jets supplied through the passages l4and oversaturated with fuel. The volume of the antechamber l3 and thatof space 8 are in the proportionof about 1:4 and the ratio ofcompression is about 1:13. Overheating of the antechamber body l2,especially with full load, is prevented by guiding the current ofcooling air for the working cylinder I so that it flows over at leastthose cooling ribs 20 of the antechamber body l2 which lie in the rangeof the working cylinder I. By selectively applying antechamber bodiesfitted with a larger or smaller number of ribs l8 and 20, respectively,

" the heat condition of theantechamber l3 can of advantage to providesymmetrically the samenumber of working cylinders on the other side ofthe crank shaft. Furthermore, as a matter of course, instead of threepassages I4, as in the embe provided. These passages, further, neednotbe circular but can have any other suitable cross section, such assquare, rectangular, or oblong cross section. Finally, the cross sectionof the passages I4 may enlarge or taper from the antechamber 13 towardthe cylinder I, or first enlarge and then taper.

The described engine operates in the four stroke cycle and can be usedwith advantage for the drive of any vehicles. In the first inward strokeof the piston I pure air is sucked into the r cylinder I through thevalve 5. On the return stroke of the piston this air is compressed up toabout 35 atmospheres above atmospheric and in part pressed into theantechamber l3. When the piston 1 is in the top dead center position,fuel is injected into the highly heated antechamber l3 through thenozzle l6 and is ignited in part by the air existing therein. Thiscauses an increase of pressure in the antechamber l3 with the resultthat the content of the latter enters the space 8 through the passagesM, where it meets the likewise very hot air and causes an intimateintermingling of the fuel particles with this air. This results in acomplete and quick combustion of'the fuel. Thereupon follow the usualexpansion and exhaust strokes.

If the described antechamber Diesel engine is to be converted into acarburetor engine, such as one fitted with spark plug ignition andcompression of the mixture, apart from the obvious replacement of thefuel feeding device by a carburetor and of the highly compressing pistonI by a piston causing a low compression of about 1:5, nothing isrequired, but to replace the antechamber body l2 by a spark plug.

'der head from the cylinder.

for a fuel injection nozzle usual with Diesel engines.

It may further be stated that in converting thev Diesel engine into alow compression engine even the exchange of the piston can be avoided byadjusting the degree of compression required in the special case byaltering the distance OI the cylin- This can be accomplished, forexample, by interposing between these two parts rings of differentheight.

What I claim and desire to secure by Letters Patent is:

' 1. In a Diesel engine for vehicles, a cylinder and reciprocatingpiston defining a combustion chamber, the walls defining said combustionchamber when the piston is at inner dead center being shaped to confinesaid combustion chamber to a trough-shaped cavity extending from a.relatively large unrestricted mouth opening toward:one side of thecylinder, across the head of the cylinder toward the opposite side, saidcavity diminishing in both heighth and breadth in the x direction awayfrom its mouth, a fuel feeding device comprisinga precombustion chambermounted in an aperture in the lateral Wall of the cylinder in positionto discharge a jet of fuel into the mouth of said cavity in thedirection of the axis of the cavity.

2. In a Diesel engine for vehicles, a cylinder and reciprocating pistondefining a combustion chamber, the walls defining said combustionchamber when the piston is at inner dead center being shaped to confinesaid combustion chamber to a trough-shaped cavity extending from arelatively large unrestricted mouth opening toward one side of thecylinder, across the head of the cylinder toward the opposite side, saidcavity diminishing in both heighth and breadth to substantially zero, inthe direction away from its mouth, and a fuel feeding device mounted inan aperture in the lateral wall of the cylinder in position to dischargea jet of fuel into the mouth of said cavity in the direction of theaxisof the cavity.

ADOLF ROTH.

